Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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157
FXUS64 KHGX 161526
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1026 AM CDT Sat Sep 16 2017

.DISCUSSION...
Widespread fog this morning continues to dissipate across SE
Texas as winds begin to pick up from the southeast. A line of
showers will be possible from La Grange down towards Matagorda Bay
this morning which lines up well with an axis of higher moisture
seen on GOES 16 derived precipitable water imagery. The rest of
the forecast looks on track with only adjustments to rain chances
based on current trends.

Overpeck

&&

.PREV DISCUSSION... /ISSUED 658 AM CDT Sat Sep 16 2017/

AVIATION...
VFR conditions at CLL, HOU, SGR, LBX, and GLS while MVFR vis in
place at UTS. CXO has been consistently dropping from IFR down to
VLIFR as a result of 1/4 FG, but expecting conditions to improve
by 13Z rising to VFR criteria. IAH also seeing patchy fog
hindering visibility down to 3/4 mi this morning, but expecting
VFR conditions to prevail for the remainder of the day by 14Z.
Expecting SGR and LBX vis to lower over the next hour and hold
till 13/14Z based off a persistence forecast and latest SREF
guidance.

Possibility of an isolated shower or two could impact the CLL TAF,
and as a result included VCSH for 14-17Z. Also expecting a BKN
deck to impact our northern sites at CLL and UTS early this
afternoon. Otherwise, expecting VFR conditions through the
remainder of the day for the rest of the TAF sites. Another round
of patchy localized fog and lower cigs will be possible again
tomorrow morning impacting the same sites as this morning.

Hathaway

PREV DISCUSSION... /ISSUED 352 AM CDT Sat Sep 16 2017/

DISCUSSION...
A couple of shortwave troughs moving across the northern part of
the state will help to slightly erode the upper level high
pressure ridge overhead of the area this morning. PWs of 1.4
inches associated with these systems could help initiate isolated
showers toward the coastal areas later today. However, model
forecast soundings show that the capping inversion due to the high
pressure aloft will be a bit tough to erode; so, any showers that
do develop will be fairly shallow and likely toward and off of the
coast.

Later today and on Sunday the upper level high pressure area will
continue to develop over the Upper Texas coastal areas as an upper
low pressure trough digs across the western part of the country.
PWs will begin to rise to between 1.9 and 2.2 by Monday as tropical
moisture streams ahead of the trough into Texas and onshore winds
at the surface advect Gulf moisture into the area. It appears that
the ridge will be too strong on Sunday for much rain development,
and best chances for showers and thunderstorms will be mainly
east of the area. However, did keep isolated chances in place for
most of the area. By late Monday Southeast Texas will be under a
westerly flow aloft as the upper ridge gets pushed southward.
Daily chances for showers and thunderstorms can then be expected
Monday through the rest of the week; although, chances do look to
diminish by Thursday. Another upper level trough will dig into the
western part of the country on Thursday and a downstream ridge is
expected to develop over or just east of the our area Thursday
and Friday. To summarize and conclude the week`s weather, the dry
period that has affected Southeast Texas since the passage of
Harvey should ease this coming week.

40

MARINE...
Light to moderate southeasterly flow is expected through the weekend
and into early next week, with low seas between 1 to 2 feet. Should
begin to see a change late Tuesday into early Wednesday as winds
pick up to between 10-15 knots mostly over the western waters due to
a tightening pressure gradient. As a result, could see periods of
building seas between 2 to 4 feet. Isolated showers and
thunderstorms associated with the afternoon sea breeze will also be
possible through early next week. Tides are continuing to run around
a half foot above normal. This trend should persist through the
weekend.

Hathaway

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      91  70  92  73  92 /  10  10  10  10  30
Houston (IAH)              91  72  91  74  90 /  10  10  20  10  40
Galveston (GLS)            87  78  87  78  86 /  10  20  30  20  40

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

Discussion...39



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